must jackknife
Verbo regular: jackknife - jackknifed- jackknifed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must jackknife
you must jackknife
she must jackknife
we must jackknife
you must jackknife
they must jackknife 	I must be jackknifing
you must be jackknifing
she must be jackknifing
we must be jackknifing
you must be jackknifing
they must be jackknifing	I must have jackknifed
you must have jackknifed
she must have jackknifed
we must have jackknifed
you must have jackknifed
they must have jackknifed	I must have been jackknifing
you must have been jackknifing
she must have been jackknifing
we must have been jackknifing
you must have been jackknifing
they must have been jackknifing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not jackknife
you must not jackknife
she must not jackknife
we must not jackknife
you must not jackknife
they must not jackknife 	I must not be jackknifing
you must not be jackknifing
she must not be jackknifing
we must not be jackknifing
you must not be jackknifing
they must not be jackknifing	I must not have jackknifed
you must not have jackknifed
she must not have jackknifed
we must not have jackknifed
you must not have jackknifed
they must not have jackknifed	I must not have been jackknifing
you must not have been jackknifing
she must not have been jackknifing
we must not have been jackknifing
you must not have been jackknifing
they must not have been jackknifing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I jackknife?
must you jackknife?
must she jackknife?
must we jackknife?
must you jackknife?
must they jackknife? 	must I be jackknifing?
must you be jackknifing?
must she be jackknifing?
must we be jackknifing?
must you be jackknifing?
must they be jackknifing? 	must I have jackknifed?
must you have jackknifed?
must she have jackknifed?
must we have jackknifed?
must you have jackknifed?
must they have jackknifed? 	must I have been jackknifing?
must you have been jackknifing?
must she have been jackknifing?
must we have been jackknifing?
must you have been jackknifing?
must they have been jackknifing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not jackknife?
must you not jackknife?
must she not jackknife?
must we not jackknife?
must you not jackknife?
must they not jackknife? 	must I not be jackknifing?
must you not be jackknifing?
must she not be jackknifing?
must we not be jackknifing?
must you not be jackknifing?
must they not be jackknifing? 	must I not have jackknifed?
must you not have jackknifed?
must she not have jackknifed?
must we not have jackknifed?
must you not have jackknifed?
must they not have jackknifed? 	must I not have been jackknifing?
must you not have been jackknifing?
must she not have been jackknifing?
must we not have been jackknifing?
must you not have been jackknifing?
must they not have been jackknifing?